topic Re: pin sharing between ADC and IO output in Kinetis Microcontrollers

pin sharing between ADC and IO output

duonghiep_set — Tue, 14 May 2019 03:40:20 GMT

Hi all,

I have a question about pin sharing between ADC and IO

My circuit use PTB3 for both ADC and IO output. In start, circuit will check a jumper to choice config PTB3 is ADC input or output.

I setup ADC and IO in figure below:

In main(), I Check jumper and set direction of PTB3 is output "CDS_SetOutput()" and blinking it, but It isn't work. The output don't change when I mount a LED in.

How can I do that??

Edit:

MCU : MKE02Z16VLC4

CW 10.7

Thanks,

Plus.

Re: pin sharing between ADC and IO output

jingpan — Thu, 16 May 2019 08:45:15 GMT

Hi,

Processor Expert can't understand your requirement. You setting is conflict to each other. You have to manually add you code. You must take care that each time you generate Processor Expert code, it may cover your own code.

Regards,

Jing

Re: pin sharing between ADC and IO output

duonghiep_set — Fri, 17 May 2019 02:59:38 GMT

Hi Jing,

Many thank for your suggestion.

I'm newbie and I am in embarrass that how to setup GPIO and ADC without PE.

I will search and try on my circuit.

Regards,

Plus.

Re: pin sharing between ADC and IO output

andy1 — Mon, 10 Jun 2019 14:54:44 GMT

You will have to write code that changes the use of the pin depending on your jumper. My suggestion is to make two configurations (builds) of your project. Each copy will be configured for one of the two specific uses alone. That way you can test that they both work independently. AND even more importantly, you can compare the PE generated code for each build and find see how the PE tool configures the pin and peripherals for each output. (use a freeware tool like Diffmerge to compare the code files in each project directory)

Once you do that, you can make a single project that can run the appropriate configuration code depending on which use you want for PTB3.

In general, you need to do two different things to switch from ADC input to GPIO output. I am using MCUExpresso and the latest Kinteis SDKs, not Processor Expert. So this is purely example code, but I expect that the solution for your situation will be similar. (BTW, Why are you using old tools like PE? I suggest updating to the current toolchain if you want to get the best help on here.)

1: Initialize the pin as an output, with an initial state of 0:

gpio_pin_config_t gpiob_pin38_config = {
.pinDirection = kGPIO_DigitalOutput,
.outputLogic = 0U
};
GPIO_PinInit(GPIOB, 3U, &gpiob_pin38_config);

2: Switch the pin MUX to GPIO, this disconnects the port from the ADC and connects it to the GPIO module:
PORT_SetPinMux(PORTB, 3U, kPORT_MuxAsGpio);

If you wanted to switch back to ADC, you would need to do a similar thing, except set the pin mux to ADC instead of GPIO:

(PORT_SetPinMux(PORTB, 3U, kPORT_PinDisabledOrAnalog);

Re: pin sharing between ADC and IO output

duonghiep_set — Wed, 12 Jun 2019 01:30:03 GMT

Thank Andrew,

Your suggestion is very helpful. I'm using PE because of many reasons like my company system, team activities..etc.

This project was be pending so my circuit is be in bottom of the cabinet. :smileygrin:

When have time, I will coding in MCUExpresso and try your code.

Regard,

Plus.